1. Field of the Invention
The present invention relates generally to mobile communication equipment and subscriber identity modules (SIMs) used in connection therewith, and more particularly to methods and apparatus for performing SIM initialization procedures with SIMs.
2. Description of the Related Art
Global System for Mobile communications (GSM) is a globally-accepted standard for digital cellular communication using mobile stations. Like most wireless technology standards, GSM standards are documented in specifications or “specs”. GSM specs originally began in committee “GSM” of CEPT (Conference of European Posts and Telecommunications). As CEPT Recommendations, they were allocated a reference number of the form “nn.nn” (for example, “GSM 06.12”). The GSM community (i.e. the Technical Committee “Special Mobile Group” or SMG) continues to use these specification identifiers even after transfer to the European Telecommunication Standards Institute (ETSI).
GSM specifications are typically grouped into “releases”. Nearly all of the specifications for all releases are published as ETSI deliverables and most have undergone several revisions in each release. The initial specifications were published by ETSI in 1994 and are now referred to as “Phase 1”. The next release was known as “Phase 2”, and the following one as “Phase 2+”. Within Phase 2+, there have been annual releases since 1996, which are known as R96, R97, R98, and R99.
One important component in GSM is a Subscriber Identity Module or “SIM” card which is inserted into mobile equipment for its operation. A SIM is a small and thin card which contains a small chip (i.e. processor and memory) which communicates with mobile equipment. A SIM stores important parameters, such as an International Mobile Subscriber Identity (IMSI), to uniquely identify an end user or subscriber of the mobile equipment. A SIM may store user information for the subscriber as well, including datebook (or calendar) information, recent call information, short message service (SMS) messages, among other data items. In addition, the processor on the SIM typically includes a set of applications and related procedures used during a GSM session, referred to as a SIM Application Toolkit. One advantage of using a SIM is that subscribers are not necessarily bound by any single physical mobile terminal, as they may carry personalized information with them for use with other terminals.
Prior to operation, a SIM initialization procedure must be performed between the mobile terminal and the SIM. A conventional SIM initialization procedure is specified in a GSM specification referred to as GSM 11.11 [14]. During conventional SIM initialization, the mobile equipment may attempt to send its terminal profile to the SIM. The terminal profile of the mobile equipment identifies to the SIM the facilities of the SIM Application Toolkit that are supported by the mobile equipment. That is, the terminal profile of the mobile equipment lets the SIM know what SIM-related features the mobile equipment is capable of so that the SIM can limit its instruction range accordingly.
However, the mobile equipment and the SIM may be manufactured in accordance with different versions or releases of the GSM specification. If so, the mobile equipment and the SIM may fail to operate together as intended. For example, the mobile equipment may be manufactured in accordance with R99, whereas the SIM may be manufactured in accordance with R98. One difference between R98 and R99 is that the terminal profile is 17 bytes in R99 but only 9 bytes in R98. In this case, the mobile equipment may receive an error from the SIM and invalidate it. Thus, the mobile equipment may fail to operate as intended even though these desirable features do indeed exist.
Accordingly, there is a resulting need for methods and apparatus for performing SIM initialization procedures that overcome such conventional deficiencies.